1. Field of the Invention
The present invention relates to an ophthalmological apparatus, such as an ocular refractive power measuring device or retinal camera, equipped with an automatic alignment mechanism.
2. Description of the Related Art
In a case where an eye to be examined (hereinafter simply called an xe2x80x9ceyexe2x80x9d) is examined or photographed through use of an ophthalmological apparatus such as an ocular refractive power measuring device or retinal camera, an optical system housing which houses an optical system must be aligned with the eye beforehand. Such alignment of the optical system housing has hitherto been performed by means of an operator manually actuating the optical system housing through manipulation of a joystick or a trackball. However, a recent ophthalmologic apparatus employs an automatic alignment mechanism which automatically aligns an optical system housing with an eye on the basis of alignment information acquired by way of an photoelectric converting element.
Such an automatic alignment mechanism can detect misalignment within a narrow range. Thus, the automatically alignment mechanism can actuate the optical system housing within the narrow range adjacent to a position where alignment of the optical system housing is to be completed (hereinafter called xe2x80x9can alignment detectable rangexe2x80x9d). Therefore, the operator must manually perform rough alignment of the optical system housing until the optical system housing enters the alignment detectable range, by means of operating manual operation means, such as a joystick, while viewing an anterior chamber image of the eye appearing on a monitor screen. In the ophthalmological apparatus equipped with an automatic alignment mechanism, the optical system housing is provided on the main unit in a movable manner. The alignment of the optical system housing is firstly performed by means of manual movement of the main unit until the optical system housing enters the alignment detectable range. When the optical system housing enters an alignment detectable range as a result of the alignment of the main unit, the automatic alignment mechanism commences operation, thereby automatically completing an alignment operation.
However, since the extent to which the optical system housing is actuated by means of the automatic alignment mechanism is nominal, it is difficult for the operator to determine commencement of operation of the automatic alignment mechanism at a glance. For example, if the automatic alignment mechanism has already commenced operation to actuate the optical system housing, in many cases the operator may continue operating the manual operation means without being aware of commencement of operation of the automatic alignment mechanism, wherewith the operator manually actuates the optical system housing through use of the manual operation means simultaneously with the optical system housing being actuated by the automatic alignment mechanism. The conventional automatic alignment mechanism computes the amount of misalignment and actuates the optical system housing to correct the misalignment on the premise that the manual operation means is not operated from a point in time at which the automatic alignment mechanism commences operation. In the event that operation of the manual operation means is continued and the automatic alignment mechanism actuates the optical system housing simultaneously with actuation of the optical system housing performed by means of operation of the manual operation means, an error arises between the computed amount of alignment and the actual amount of alignment. As a result, the optical system housing is excessively actuated to be out of the alignment detectable range again, thereby resulting in consumption of much time before completion of the alignment operation.
In order to avoid such problems, the ophthalmological apparatus described in Japanese Patent Application Laid-Open No. 10225/1996 is designed such that commencement of operation of the automatic alignment mechanism is informed to the operator by means of a message appearing on a monitor. However, the operator encounters difficulty in stopping operation of the manual operation means just upon receipt of such information. Hence, the optical system housing cannot be actuated by only an appropriate amount, thus resulting in consumption of much time before completion of the alignment.
U.S. Pat. No. 5,587,748 describes an ophthalmological apparatus which electrically revokes drive of the optical system housing based on operation of the manual operation means after the automatic alignment mechanism has commenced operation. However, such a system cannot be applied to a case where the manual operation means is embodied as a mechanical joystick.
The present invention has been: conceived to solve the drawbacks of the conventional art and is aimed at providing an ophthalmological apparatus capable of preventing a delay in completion of the alignment of an optical system housing, which would otherwise be caused when an automatic alignment mechanism actuates the optical system housing simultaneously with manual operation means actuating the optical system housing, even in a case where a mechanical mechanism is adopted as manual operation means.
To attain the above object, according to a first aspect to the invention, there is provided an ophthalmological apparatus including:
a main unit section having a movable optical system housing which houses an optical system for shooting or examining an eye to be examined;
a manual operation unit manually positioning the main unit section;
an alignment chart projection unit projecting onto the eye an chart luminous flux for alignment;
a chart detection unit detecting the reflected luminous flux of the chart luminous flux reflected on the eye;
an alignment unit actuating the optical system housing on the basis of a detection result of the chart detection unit in a case where the main unit section is positioned by the manual operation unit so that the chart detection unit detects the reflected luminous flux, such as to move the optical system housing with respect to the main unit section;
a position information detection unit detecting information about variations in position of the main unit section caused by the manual operation unit during the operation of the chart detection unit; and
a correction unit correcting the actuating amount of the optical system housing on the basis of a detection result of the position information detection unit.
Further, according to a second aspect of the invention, in the ophthalmological apparatus of the first aspect, the position information detection unit detects a moving distance of the main unit section between a predetermined reference time and a time after a preset time has elapsed from the predetermined reference time.
In addition, according to a third aspect of the invention, the ophthalmological apparatus of the second aspect, further includes: a notice unit noticing an operator that the detection of the chart detection unit is commenced, wherein the preset time is set so as to correspond to a period from when a notice is issued from the notice unit until the operator stops the operation of the manual operation unit in response to the notice.
Moreover, according to a fourth aspect of the invention, in the ophthalmological apparatus according to third aspect, the preset time is set to be sufficiently longer than an averaged period from when the notice is issued from the notice unit until the operator stops the operation of the manual operation unit in response to the notice.
According to a fifth aspect of the invention, there is provided an ophthalmological apparatus including:
a main unit section having a movable optical system housing which houses an optical system for shooting or examining an eye to be examined;
a manual operation unit manually positioning the main unit section; an alignment chart projection unit projecting onto the eye an chart luminous flux for alignment;
a chart detection unit detecting the reflected luminous flux of the chart luminous flux reflected on the eye;
an alignment unit actuating the optical system housing on the basis of a detection result of the chart detection unit in a case where the main unit section is positioned by the manual operation unit so that the chart detection unit detects the reflected luminous flux, such as to move the optical system housing with respect to the main unit section;
a moving speed detection unit detecting a moving speed of the main unit section caused by the manual operation unit during the operation of the chart detection unit; and
a correction unit correcting the actuating amount of the optical system housing on the basis of a detection result of the moving speed detection unit.
Further, according to a sixth aspect of the invention, in the ophthalmological apparatus according to the fifth aspect, the moving speed detection unit detects a moving speed of the main unit section at a predetermined reference time and a moving speed of the main unit section at a time after a preset time has elapsed from the predetermined reference time.
In addition, according to a seventh aspect of the invention, the ophthalmological apparatus according to the sixth aspect, further includes: a notice unit noticing an operator that the detection of the chart detection unit is commenced, wherein the preset time is set so as to correspond to a period from when a notice is issued from the notice unit until the operator stops the operation of the manual operation unit in response to the notice.
Moreover, according to an eighth aspect of the invention, in the ophthalmological apparatus according to the seventh aspect, the preset time is set to be slightly longer than an averaged period from when the notice is: issued from the notice unit until the operator stops the operation of the manual operation unit in response to the notice unit.
According to a ninth aspect of the inveniton, there is provided an ophthalmological apparatus including:
a main unit section having a movable optical system housing which houses an optical system: for shooting or examining an eye to be examined;
a manual operation unit manually positioning the main unit section;
an alignment chart projection unit projecting onto the eye an chart luminous flux for alignment;
a chart detection unit detecting the reflected luminous flux of the chart luminous flux reflected on the eye;
an alignment unit actuating the optical system housing on the basis of a detection result of the chart detection unit in a case where the main unit section is positioned by the manual operation unit so that the chart detection unit detects the reflected luminous flux, such as to move the optical system housing with respect to the main unit section;
a moving speed detection unit detecting a moving speed of the main unit section caused by the manual operation unit during the operation of the chart detection unit; and
an actuation permission unit permitting a commencement of the actuation of the optical system housing according to the alignment unit on the basis of a detection result of the moving speed detection unit.